---

yaml
---
r: 205220
b: refs/heads/master
c: f5155b3
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 551d55a944b143ef26fbd482d1c463199d6f65cf
+refs/heads/master: f5155b33277c9678041a27869165619bb34f722f

trunk/include/linux/rcupdate.h

@@ -566,4 +566,37 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
 }
 #endif	/* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
 
+#ifndef CONFIG_PROVE_RCU
+#define __do_rcu_dereference_check(c) do { } while (0)
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
+#define __rcu_dereference_index_check(p, c) \
+	({ \
+		typeof(p) _________p1 = ACCESS_ONCE(p); \
+		__do_rcu_dereference_check(c); \
+		smp_read_barrier_depends(); \
+		(_________p1); \
+	})
+
+/**
+ * rcu_dereference_index_check() - rcu_dereference for indices with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * Similar to rcu_dereference_check(), but omits the sparse checking.
+ * This allows rcu_dereference_index_check() to be used on integers,
+ * which can then be used as array indices.  Attempting to use
+ * rcu_dereference_check() on an integer will give compiler warnings
+ * because the sparse address-space mechanism relies on dereferencing
+ * the RCU-protected pointer.  Dereferencing integers is not something
+ * that even gcc will put up with.
+ *
+ * Note that this function does not implicitly check for RCU read-side
+ * critical sections.  If this function gains lots of uses, it might
+ * make sense to provide versions for each flavor of RCU, but it does
+ * not make sense as of early 2010.
+ */
+#define rcu_dereference_index_check(p, c) \
+	__rcu_dereference_index_check((p), (c))
+
 #endif /* __LINUX_RCUPDATE_H */